Assessments of porosity effects on mechanical behavior and scratch tests onto the AISI 316L steel obtained using additive manufacturing (DMLS) and sintering (SPS)

Abstract

This project aims to analyze the porosity effect based on scratch tests onto AISI 316L steel specimens, which are obtained from two manufacturing processes: additive using Direct Metal Laser Sintering (DMLS), and sintering via Spark Plasma Sintering (SPS). The experimental procedure consists in conducting microscratch tests of the austenitic stainless steel specimens, comparing the mechanical behavior and tribological responses (e.g friction coefficient and material removal) of the materials derived from different manufacturing processes. In these tests, the input parameter is the constant normal force to be applied to characterize the dominant abrasive mechanism for each condition. In turn, this tribological approach tends to incorporate mechanical and microstructural aspects, consisting of plastic deformation, topography, and surface finishing, for instance. Therefore, the experimental-numerical methodology employs the mechanical characterization by instrumented indentation, and Vickers microhardness; microstructural characterization using SEM and DRX; roughness measurements of specimens with different porosities; and evaluation about abrasion micro-mechanisms and energy dissipated due to the scratching. Additionally, investigations focused on the stress triaxiality variation as a function of the localized influence of pores and other material heterogeneities, and subsurface results after the scratch tests, can be promoted. To reach this goal, numerical simulations by finite elements (FEM) are utilized to provide explanations in terms of stress and strain fields, closing/deformation of pores, residual stress, and strain-hardening. To conclude, this research intends to make an investigation due to the design of materials and microstructural definitions, which can be helpful in view of biomaterials. Collaborations are taken as very important to broad and complement knowledges related to material, manufacturing processes and mechanical behavior in experimental and numerical approaches. (AU)